Yes-Man is an AI unit in 2281, He is Benny's assistant also takes a part of Benny's plan to take over of New Vegas.Yes Man's personality inhabits a PDQ-88b Securitron later assists the Courier in the independent New Vegas options for the game's ending as the Lucky 38's mainframe.
Yes-Man was a Securitron robot programmed to work for Mr. House, like the other Securitrons found on the Strip, However, Yes-Man was damaged by a pulse grenade, and was helped by Benny and a few of the Chairmen, they then allowed Emily Ortal to examine the Securitron for Mr. House's secrets, in exchange for reprogramming him.
The reprogramming was extensive, and resulted in Yes-Man being designed to do exactly as he is told (although the lack of restrictions as to who is doing the ordering would later be Benny's undoing). The plan was to dispose of Mr. House, plant Yes-Man's A.I. in the Lucky 38 mainframe which would then put Yes Man (and by extension, Benny) in control of all the other Securitrons on the Strip. The next step was to take the platinum chip to The Fort, where he would take control of the great weapon he suspected Mr. House to have hidden away (as he did not know exactly what was stored there). The last step in the plan was to use this "weapon" to assume control of New Vegas and Hoover Dam.
Yes-Man can also be found after Benny has been assassinated by the Courier at The Tops. To find Yes-Man, enter the Tops casino and proceed straight ahead past the casino floor to banks of elevators (near the sign that says "Elevators out of Order"). Take the second elevator on the right to the 13th floor. Exit the elevator, turn right, and enter the third set of doors on the left side of the corridor (double doors with potted trees flanking them). Go into the room and through the hole in the wall.